Enzyme-Based Electrochemical Multiphase Microreactor for Detection of Trace Toxic Vapors

A dual microchannel device with a gas-liquid interface was developed for use as an amperometric biosensor for the detection of organophosphate chemicals based on acetylcholinesterase inhibition. Electric eel acetylcholinesterase was immobilized on the liquid microchannel by creating a cross-linked gel with glutaraldehyde. The system was tested with malathion, an organophosphorus pesticide. The detection limit of the sensor is in the parts-per-trillion range and the detection is rapid, sensitive, and selective to only phosphonates. Incorporation of existing acetylcholinesterase biochemistry into a microscale sensor improves the sensitivity of the device by about an order of magnitude and the reaction speed by two orders of magnitude. Also, a microscale sensor allows the device to be easily portable.